ASIO Optimization for your E-MU Digital Audio System

E-MU's Technical Support department offers some tips on how to optimize ASIO performance on your PC and reduce latency.

ASIO (Audio Stream Input/ Output) is the driver of choice for many professional desktop audio applications, sitting between your computer's audio hardware and your DAW software such as Cubase, Nuendo, or Sonar. E-MU's line of Digital Audio Systems makes excellent use of this robust multi-channel audio driver with comprehensive implementation of the latest that ASIO has to offer, with full 24-bit/192kHz support.

Although E-MU's Digital Audio Systems feature zero-latency Direct Monitoring (for those audio applications that support it), optimizing your PC ASIO setup is critical for proper recording and playback. For those audio applications that don't support ASIO Direct Monitoring, proper implementation of ASIO and a well-tuned PC allows for latency so low (2 to 5 ms) that it is hard to detect by the human ear, allowing musicians to monitor their performance in time with the backing tracks. In either case, your system will greatly benefit from the following tweaks.

BIOS level:
Set your PCI Bus latency to a minimum of 64 cycles- higher should be OK. If it's too high you may end up with graphics problems. If that's the case lower it. 64 to 128 cycles works best for most systems.

Turn off Legacy USB mode (note that this will prevent the use of USB mice and keyboards until Windows has booted)

Always make sure your BIOS is updated. Check with the BIOS and motherboard manufacturers website for the latest BIOS updates.

Turn off motherboard sound hardware. It's poor quality and will occupy PCI bus space for no good reason.

System level:
Never run instant messaging software while using your PC for audio production.

Always disable your antivirus software before using your PC for desktop audio production. Tests show that antivirus software is powerless against the types of viruses associated with musicians and vocalists. If you are concerned about this, use Lysol and wash hands frequently.

Disable your network connection. While having internet access on your audio production PC can be great for updates and registering your product, you want it disabled when making music. Go to Start/Settings/Network Connections/ find your network connection, right click on it and choose disable. To re-enable the network connection repeat the steps and choose enable.

Go to System/Properties/Advanced/Performance/Settings and set your system to "best performance".

Optimize your processor scheduling for audio. To use ASIO at lowest latencies under Windows 2000/XP single CPU systems, the 'system performance' should be optimized for background tasks. Go to Control Panel/System/Advanced/Performance Options. Change the default 'Applications' to 'Background tasks'. This can have a significant impact on ASIO latency.

Deactivate ACPI:
Note: The following tip is for advanced Windows users only. All others should consult a computer tech for assistance with this procedure!!!

Generally Win2k users should not use ACPI mode on their desktop audio production PC's. ACPI (Automatic Configuration Power Interface) was designed as a tool to prevent IRQ issues associated with PCI cards. It is generally considered very bad for robust audio applications under Win2k. It is important to know that ACPI is more of a problem in Win 2k then XP. Many XP users do not encounter ACPI related problems.

To determine if you need to deactivate ACPI do the following:

Go to the Start menu and click on "Run".

Now enter "msinfo32". This starts the system information program.

On the left hand side you can see a 'tree' view, similar to those used in the Explorer. Click on the left on "Hardware Resources" and then on "IRQs".

On the right hand side, there should appear a list of your devices with the respective IRQ to which they have been assigned. Check if devices (especially your E-MU audio card) share an IRQ with other devices. If this is the case, then you should deactivate ACPI.

How to deactivate ACPI before installing Windows (recommended method):

Backup your system using Norton Ghost or another backup/recovery program.

Before installing your Windows OS go into your BIOS and set Plug and Play OS to No.

During installation hit F6 when you are asked for updated device drivers (blue screen).

Then press F5 and choose Standard-PC.

How to deactivate ACPI after having installed Windows (not recommended- proceed at your own risk):

Backup your system using Norton Ghost or another backup/recovery program.

Set the Plug and Play OS option in your BIOS to No.

Once booted go to your Device Manager, click on Computer then double click on ACPI-PC. Go to Driver/Update Driver.

Now select 'Display a list of known drivers for this device', then select 'Show all Hardware of this device class'.

Now select Standard PC in the right hand window. Windows will then reboot and reinstall all hardware using your BIOS's IRQ assignments.

The assignment to Standard PC bears risks and is not recommended by Microsoft. You may have to reinstall Windows and select the Standard PC mode during the installation. Further information you can find in the Microsoft knowledgebase (support.microsoft.com).

You will find many excellent tips for PC optimization for audio at the following websites:

Drive maintenance:
It is important to have your hard drives optimized for streaming audio as well. Because hard drive tweaks vary from manufacturer to manufacturer here are some basics for hard drive audio optimization in the event you suspect drive problems:

Defrag your drive. Go to Start/Programs/Accessories/System Tools/Disk Defragmenter/. Your media drive (the drive you record audio to) should be defragged regularly. Defrag even if it tells you the drive is only 1% or 2 % fragmented.

DMA enable your drive. For Windows XP, Direct Memory Access is not set for individual Hard Drives and CD Rom Drives. Instead, DMA is set for the Primary IDE Channel and the Secondary IDE Channel. These devices can be a combination of Hard Disk Drives, CD Rom Drives, CDRW Drives, DVD Drives and Tape Backup Drives etc. Therefore, if both channels are set for DMA access, then all the devices in your system will be set to use DMA.

Here's how to set DMA for your drives under Windows XP.

Go into your Control Panel by first clicking on the Start Button.

Then click on Settings, then Control Panel.

Then double click on the System icon to open up the System Properties window.

Now click on the Hardware tab located at the top of the screen.

Then click on the Device Manager button in the center area of the screen.

Now click on the plus sign [+] next to the IDE ATA/ATAPI controllers to expand that section.

Then double click on the Primary IDE Channel to display the Primary IDE Properties window.

Then click on the Advanced Settings Tab at the top of the screen.

Now for Device 0, ensure that the Transfer Mode: selection is set to DMA if available.

Then for Device 1, ensure that the Transfer Mode: selection is also set to DMA if available.

Then click on the OK button at the bottom of the screen to save your settings.

Then double click on the Secondary IDE Channel to display the Secondary IDE Properties window.

Then click on the Advanced Settings Tab at the top of the screen.

Now for Device 0, ensure that the Transfer Mode: selection is set to DMA if available.

Then for Device 1, ensure that the Transfer Mode: selection is also set to DMA if available.

Then click on the OK button at the bottom of the screen to save your settings.

Then close Device Manager and the Control Panel to return back to your Windows session.

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